长期施肥对砂姜黑土丛枝菌根真菌群落的影响

在农业生态系统中,丛枝菌根真菌(AM真菌)与很多作物的根系都存在互惠互利的共生关系,与作物的生长和健康密切相关,同时,这类特殊的真菌群落也会受到施肥等农业措施的影响.本研究依托长期定位试验4个试验处理(不施肥、单施化肥、化肥配施秸秆、化肥配施粪肥),研究砂姜黑土AM真菌群落对不同施肥措施的响应及其影响因素,探索不同处理AM真菌指示种的存在.结果表明: 砂姜黑土中的主要AM真菌类群为原囊霉科、多孢囊霉科、巨孢囊霉科、近明球囊霉科、球囊霉科和类球囊霉科;其中类球囊霉属在化肥和有机物料配施中具有显著指示作用.与对照相比,长期单施化肥显著改变AM真菌群落结构并降低其多样性,配施秸秆处理进一步降低AM真菌群落多样性,而配施粪肥明显缓解因施用化肥而造成的多样性减少现象.检验发现,导致AM真菌群落变化最主要的影响因素是土壤pH和可溶性碳.总之,长期不同有机物料和化肥配施对砂姜黑土AM真菌群落结构和多样性会产生不同影响,其中化肥配施粪肥更有利于土壤AM真菌群落多样性的维持.

Effects of long-term fertilization on arbuscular mycorrhizal fungal community in lime concretion black soil

In agroecosystem, arbuscular mycorrhizal fungi have mutually beneficial symbiosis with roots of many crops. Meanwhile, this special fungal community is also affected by agricultural mana-gements such as fertilization. The objective of this study was to investigate the effects of long-term fertilization managements (no fertilizer, chemical fertilizer, chemical fertilizer combined with straw, chemical fertilizer combined with manure) on arbuscular mycorrhizal fungal community (AM fungal community) in lime concretion black soil, and to identify the indicator species in each fertilization regime. The most dominant arbuscular mycorrhizal fungal phyla in lime concretion black soil were Archaeosporaceae, Diversisporaceae, Gigasporaceae, Claroideoglomeraceae, Glomeraceae and Paraglomeraceae. The genus Paraglomus was strongly and significantly associated with the application of chemical fertilizer and organic fertilizer. Compared with the control, long-term application of chemical fertilizer greatly changed AM fungal community structure and resulted in the decrease of AM fungal diversity, and the addition of wheat straw further decreased the diversity, while the addition of manure could alleviate diversity loss resulted from chemical fertilization. Soil pH and dissolved organic carbon (DOC) were the main factors affecting the changes of AM fungal community. In summary, long-term application of chemical fertilizer combined with different organic materials had different impacts on soil AM fungal community structure and diversity. The combination of chemical fertilizer and manure would be more conducive to the maintenance of AM fungal diversity.